In chromatography the output from a chromatograph is called a chromatogram. Generally, a chromatogram is a hard-copy plot of detector output voltage versus time. Ideally, the voltage would appear as a Gaussian-shaped peak, or series of such peaks. For qualitative analytical applications of chromatography, it is essential to know the retention time, i.e., the elapsed time from the start of the chromatogram to the maximum voltage of the peak. For quantitative analysis with a chromatograph it is necessary to know the retention time and the area under the voltage-time peak.
In the current practice of chromatography, the measurement of retention times and peak areas is generally done by electronic integrators. Such chromatographs usually provide hard-copy records of peak areas and retention times in suitable units.
Under ordinary conditions the chromatographer has no method available, other than standard sample injection, to calibrate the output of the integrators. Even with standard sample injection, it must be assumed that the chromatograph is functioning properly.
It is therefore a specific aspect of the present invention to provide apparatus useful in calibrating the output of such chromatographs.